Vozrozhdeniye
Pournelle has long been my favorite PC authority, and his comments here underline the fact that he is not only a good writer, but a clear thinker as well.
Of the three sources Pournelle mentions, I'd lean toward the former USSR. See Dan's post <a href="http://www.habitablezone.com/currentevents/messages/17940.html>below about the former island (Vozrozhdeniye) in the Aral Sea where the Soviets conducted some of their biowarfare research.
This is a likely source for the anthrax.
sp